Text can be bold or italics and can have links embedded.
You can put in images from the web with a url:
wikibou
Or put in local images using a relative path:
wikibou
You can have a bulleted list:
Or a numbered list:
For certain things you’ll need to use HTML. For example, audio could be put in the page by using soundcloud embed code:
Or, if the files are local, with:
You can also use HTML to center an image, Markdown will align them left usually.